On the most recent update (today, 25 Aug 2014) of US maps, many interchanges are buggy. The worst I've found so far is the NJ turnpike (I95) at NJ73, where the road becomes non-continuous and is therefore unroutable. Many bugs in VA and MD as well (double slip roads instead of staying on the interstate). Multi-lane, HOV, and restricted splits are generally problematic on routing too... osm does not recognise the inner lanes as part of the same road.

Also, there is no means to set toll/charge/congestion road characteristics, only to disable/enable them on android.

(As a feature request after spending 3 hours trying to put in my own experience routing shortcuts and having to do so via disabling links and (occasionally) waypoints, it would be quite nice to have a 'force link' as well as a 'disable/enable link'. I suspect it would help bug discovery as well.)